Discuss the fourth dimension in "Fifty Grand."

The kind of writing that can be done. How far prose can be carried if anyone is serious enough and has luck. There is a fourth and fifth dimension that can be gotten. -Ernest Hemingway, Green Hills of Africa

What Hemingway meant by a "fourth dimension" seems easier to apprehend in "Fifty Grand" than in any of his other short stories. The first three dimensions are height, width and depth. The fourth must have something to do with time. Events occur outside the text--before, during, and after what is being described or dramatized--which are so essential to the chain of cause and effect that the reader "will have a feeling of those things as strongly as though the writer had stated them."
A good example involves Jack Brennan's "jam" with Soldier Bartlett. Soldier is a loudmouth ignoramus. He treats Jack disrespectfully because he can tell, from sparring with him day after day, that Jack is losing everything that made him champion. Soldier is thinking he could beat Jack himself if he were challenger instead of Walcott. Finally Jack is fed up with Soldier's so-called "kidding" and fires him.
The story's opening takes place in a joint where the fight crowd hangs out. The outraged Soldier must head back there (in the fourth dimension) because he has nowhere else to go. Naturally everybody wants to know why he is in Hanley's when Jack is still training in New Jersey. They also ask what Soldier thinks about Jack's condition and chances of winning the big championship fight. We can visualize these scenes because Hemingway has introduced us to the place for that purpose.
Soldier enjoys being the center of attention, and he has nothing good to say about the champion. He tells everybody he got fired because Jack knows he is going to lose and is sore at the world, or words to that effect. Soldier--a washed-up, third-rate pug--probably voices his opinion that he could beat Jack himself, although he had an opportunity to try it when they were doing roadwork.

"Well," says Jack, "you better go back to town, Soldier.""What do you mean?""You better go back to town and stay there.""What's the matter?""I'm sick of hearing you talk.""Yes?" says Soldier.|"Yes," says Jack."You'll be a damn sight sicker when Walcott gets through with you.""Sure," says Jack, "maybe I will. But I know I'm sick of you."

Jack twice tells Soldier, not that he is fired, but that he better go back to town. This is to foreshadow where Soldier will be going and what will happen. Soldier might have even claimed he wasn't fired but quit because he decided Jack was hopeless, or because he was hitting Jack too hard.

So Soldier went off on the train to town that same morning. I went down with him to the train. He was good and sore.
"I was just kidding him," he said. We were waiting on the platform. "He can't pull that stuff with me, Jerry."
"He's nervous and crabby," I said. "He's a good fellow."
"The hell he is. The hell he's ever been a good fellow."
"Well," I said, "so long, Soldier."

Hemingway wants to impress the reader with the fact that Soldier is going back to Manhattan. He even has Jerry Doyle see him off on the train. This is the last we see of Soldier Bartlett, who is good and sore--but his shadow will haunt the remainder of the story.
Naturally Happy Steinfelt and Lew Morgan hear Soldier is back earlier than expected. They want to talk to him because they are taking a lot of bets both ways. What they learn inspires them to visit Jack's manager John Collins (still in the fourth dimension) and leads into the next scene at Danny Hogan's health farm.

That afternoon John Collins showed up out at the farm. Jack was up in his room. John came out in a car from town. He had a couple of friends with him. The car stopped and they all got out.

They come out of the fourth dimension. This is no social visit. They are there because Jack fired Soldier and Soldier went back to Hanley's and told everybody that Jack was sure to lose to Walcott. Who would know better than Jack's own sparring partner? Steinfelt and Morgan have already explained their proposition to John Collins, and now they are all going to present it to Jack.
What might be called the "obligatory scene" between Soldier and the crowd at Hanley's and then focusing in on a conversation between Soldier and Steinfelt or Soldier and Morgan is a good example of what Hemingway meant by the fourth dimension. (A fifth dimension would probably be a dimension of the fourth dimension. In other words, if the reader's sense of what happens in the fourth dimension is sufficiently vivid, it could give the imaginary scene depth as well as height and width. But let us remain in the fourth dimension, which is shadowy enough. Hemingway may never have felt he achieved a fifth dimension, although he believed it was possible.)
There are many other fourth-dimensional scenes in "Fifty Grand," but the ones involving Soldier back at Hanley's are the most palpable. The discussion of the proposed bet in Jack's room occurs entirely in the fourth dimension. An amusing example occurs while Doyle is killing time outdoors.

Hogan was out in the gym in the barn. He had a couple of his health-farm patients with the gloves on. They neither one wanted to hit the other, for fear the other would come back and hit him.

This is a rather uncanny pre-enactment of exactly what is going to happen at Madison Square Garden. Walcott will be extremely reluctant to hit Jack, even lightly, for fear that Jack will fall over and take the count. The same will be true for Jack, since both boxers are anxious to lose. Jerry Doyle knows that Collins, Morgan, Steinfelt, and Jack are all talking about fixing the fight. Then Doyle goes out for a walk and sees two men who are afraid to hit each other in the ring. He might have had a faint premonition of what was going to happen in the fourth dimension at Madison Square Garden in the near future.

If a writer of prose knows enough of what he is writing about he may omit things and the reader, if the writer is writing truly enough, will have a feeling of those things as strongly as though the writer had stated them. The dignity of movement of an ice-berg is due to only one-eighth of it being above water. --Ernest Hemingway, Death in the Afternoon